Electric propulsion assembly for an aircraft

Abstract

An electric propulsion assembly for an aircraft includes a nacelle having a nacelle cowl which defines an inner space for arranging an electric propulsion unit, which includes a blower, of the aircraft. An electric motor assembly is placed in the inner space and connected to the propulsion unit to supply power to the propulsion unit. An airflow generated by the blower flows in a space between the motor assembly and the nacelle cowl defining a duct to supply thrust to the aircraft. A power electronics system has at least one heat exchanger to transfer thermal energy from the system to a work fluid to cool the system. The heat exchanger is placed to project at least partially into the duct, so that the work fluid consists of the air flow generated by the blower.

Claims

1. An electric propulsion assembly for an aircraft comprising: a nacelle comprising a nacelle cowl delimiting an internal volume to place an electric propulsion unit of the aircraft comprising a fan, an electric motor assembly connected to the electric propulsion unit to supply an electrical energy to the propulsion unit and a control system comprising a power electronics system, a space delimited between the motor assembly and the nacelle cowl defining a duct through which an air stream generated by the fan flows to supply the aircraft with a thrust; the power electronics system comprises at least one heat exchanger to transfer a heat energy from the power electronics system to a working fluid to cool the power electronics system; and said at least one exchanger is positioned to at least partially project inwardly from the nacelle cowl into the space delimited between the motor assembly and the nacelle cowl so that the working fluid consists of the air stream generated by the fan.

2. The electric propulsion assembly as claimed in claim 1, wherein the power electronics system comprises a power electronics module and an electronic control board, said at least one heat exchanger is connected to the power electronics module and the electronic control board to remove heat dissipated by the power electronics module and the electronic control board by the Joule effect, an assembly formed by the power electronics module and the electronic control board is in the nacelle cowl.

3. The electric propulsion assembly as claimed in claim 1, wherein the nacelle defines a longitudinal axis; and wherein the electric motor assembly is connected to the nacelle by one or more sets of arms directed radially or substantially radially with respect to the longitudinal axis, at least some of the arms are configured to provide a passage to at least one of electrical connections and transmitting command signals.

4. The electric propulsion assembly as claimed in claim 1, wherein the nacelle defines a longitudinal axis; and wherein the electric motor assembly is connected to the nacelle by one or more sets of arms directed radially or substantially radially with respect to the longitudinal axis, at least some of the arms comprises at least one cooling scoop to deflect some of the air stream generated by the fan towards the electric motor assembly to cool the electric motor assembly.

5. The electric propulsion assembly as claimed in claim 1, wherein said heat exchanger comprises fins, the fins are arranged to be positioned in a direction in which the air stream generated by the fan flows so as not to disturb the flow of the air stream.

6. The electric propulsion assembly as claimed in claim 1, wherein the power electronics system comprises an additional cooling device to cool the power electronics system.

7. An aircraft equipped with at least one propulsion assembly as claimed in claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages, objects and particular features of the present invention will emerge from the description which will be given, by way of entirely nonlimiting explanation with reference to the attached drawings in which:

(2) FIG. 1 is a perspective view of a propulsion assembly according to one particular embodiment of the present invention,

(3) FIG. 2 is a longitudinal section of the assembly of FIG. 1.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

(4) It will be noted first of all that the figures are not to scale.

(5) FIGS. 1 and 2 show a hybrid electric propulsion assembly for an airplane according to a preferred embodiment of the invention.

(6) This propulsion assembly comprises a nacelle 10 intended to be assembled by means of a mechanical connection 11 such as a pylon to a structural element of an aircraft 26. Purely by way of illustration, this structural element could be part of the wing structure of the aircraft, the assembly for example being positioned at the tip of this wing structure. This assembly could, however, be attached to some other point of the wing structure of this aircraft.

(7) The nacelle 10 comprises a nacelle cowl 22 delimiting an internal volume in which an electric motor 12 that drives a fan 13 installed in front of this electric motor 12 is positioned. The nacelle 10 is arranged coaxially around the electric motor 12 about a longitudinal axis 14.

(8) Simplistically, this propulsion assembly draws in external air at an air inlet 15 of the nacelle 10 using the fan 13 which has a ducted propeller, this fan 13 comprising a nose bullet 16. This stream of air drawn in and accelerated by the fan 13 is ducted through an annular space 17 defined between the exterior surface of the electric motor 12 and the internal wall of the nacelle cowl 22, toward a nozzle.

(9) The nacelle 10 is connected directly to the tip of the wing using known techniques, allowing loads to be reacted in all directions. The nacelle 10 is mechanically connected to the electric motor 12 by one or more sets of arms 18, directed substantially radially with respect to the longitudinal axis 14.

(10) The nacelle 10 further has a continuous exterior surface, which means to say one that has no discontinuities over at least the forward half of its length in the direction in which the air flows, so as to encourage laminar flow of air around the nacelle 10.

(11) The propulsion assembly further comprises a control system comprising a power electronics system comprising a power electronic module 19 and an electronic control board 20 which are connected to a heat exchanger 21 so as to remove the power dissipated by these elements by Joule effect.

(12) Whereas the power electronics module 19 and the electronic control board 20 are housed in the cowl of the nacelle 10, the heat exchanger 21 is positioned so that it projects into the annular space 17 that separates the exterior surface of the electric motor 12 from the interior surface of the cowl of the nacelle 10.

(13) It is thus possible to take full advantage of the forced stream of air generated by the fan 13 to effectively cool the heat exchanger 21 thereby making it possible to optimize this heat exchanger 21 in terms of mass and volume so that its weight is limited as much as possible.